1. Field of the Invention
The present invention relates to an instrument for testing electric lamps, more particularly linear arrays of lamps. The novel instrument determines presence of burned out lamp filaments and open circuits in lamp arrays. The invention may be utilized by ordinary consumers and by maintenance and installation personnel to analyze operative status of Christmas lights and other linear arrays of lamps.
2. Description of the Prior Art
Most occupants of households, offices, and other living and working spaces who celebrate holidays such as Christmas and New Years Day in part by adorning structures and plants with linear arrays of lamps, hereinafter referred to as light strings, reuse light strings year after year. Over time, some of the individual lamps become inoperable due to filament failure or breakage of conductors conducting electrical power. Lamps can usually be easily replaced. Lamp replacement is less expensive than replacing a string of lights.
When one lamp fails, depending upon the circuitry of the light string, all lamps fail to illuminate or alternatively, the affected lamp fails. It is an easy matter to remove a lamp and connect it to appropriate electrical power, then to observe the results. The prior art has proposed testers designed to test individual lamps to facilitate repair of faulty light strings. An example is seen in U.S. Pat. No. 5,047,721, issued to Earl T. Farley on Sep. 10, 1991. Farley utilizes amplified capacitive discharge to determine whether an operable or defective lamp has been inserted into his tester, requiring a much more complicated circuit than does the present invention, and provides for only one type of test. The present invention offers two possible tests for each lamp being tested. Farley tests lamps in situ, i.e., with lamps connected to their associated light string. In the present invention, lamps are removed for insertion into the tester.
U.S. Pat. No. 5,179,339, issued to Robert C. Volk, Jr. on Jan. 12, 1993, describes a tester comprising a power supply which can be connected to each lamp in situ. A probe having two electrodes connects each lamp to power. If the lamp being tested is good, it illuminates when connected. By contrast, the present invention provides two tests. In one test, which connects power to the lamp being tested, the lamp is removed from the string and inserted into the tester. The lamp is inserted into the tester, albeit at a different location, for the other test.
U.S. Pat. No. 5,319,312, issued to Rocco F. Segilia on Jun. 7, 1994, sets forth a tester which is connected to a socket in the light string. The light string is thus divided into two legs. The tester of Segilia indicates which leg contains a problem area. The device of Segilia is subject to being inoperable if one lamp in each leg is defective. Progressive tests will eventually pinpoint the problem area by subdividing the leg indicated as having the defect. By contrast, lamps are removed individually and inserted into the novel tester. Segilia lacks the two tests offered by the present invention.
U.S. Pat. No. 5,369,363, issued to Bill L. Hey on Nov. 29, 1994, provides a device which extracts a lamp from its socket of the light string. The device has electrodes which apply power to the lamp. The lamp itself illuminates if it is operable when connected to power from the tester. By contrast, the present invention offers two different tests.
U.S. Pat. No. 5,539,317, issued to John L. Janning on Jul. 23, 1996, describes a tester which employs audio amplification of a field given off by a powered lamp inserted into the tester. The present invention does not use audio amplification, and in a further distinction offers two types of tests rather than one.
U.S. Pat. No. 5,604,436, issued to Charles L. Henritzy on Feb. 18, 1997, describes a tester wherein both the tester and the lights are powered when testing. The tester of Henritzy has a probe which inserted into the base of a lamp being tested to apply power thereto. Henritzy connects his tester to AC power, rather than having a battery, as does the present invention. Also, Henritzy offers but one type of test, whereas the present invention offers two different types of tests.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention sets forth a tester for light strings which tests lamps individually, after they are removed from the string and inserted into the tester. The tester has two sockets for receiving each lamp, each socket providing a different type of test. This approach is considered superior to testing lamps en masse by the user since more than one lamps can fail in a string. Potentially, failure of plural lamps defeats some testing procedures, which must then be modified to test lamps one at a time. Another advantage of testing lamps individually is that such a procedure is equally applicable to different wiring schemes utilized with light strings.
It is possible that a test will result in a false reading. Providing two types of tests substantially improves chances of successfully detecting a faulty lamp. The tester is also inherently safe since it avoids connection of either the light string or of the tester itself to household AC power, which is typically 110 to 120 volts.
The tester is small and conveniently held in the hand. It has a light emitting diode and a buzzer as indicators. Power is supplied from battery cells contained in the tester. Preferably, the cells are AA size, which are inexpensive and readily available. Use of battery power rather than household AC power eliminates errors which may arise due to inappropriate polarity when connected to AC power. The circuitry of the novel tester is such that a lamp being tested need merely be inserted into one of the two available testing sockets formed in the housing.
Accordingly, it is one object of the invention to provide a hand held tester for testing lamps of a lighting string.
It is another object of the invention to offer two different tests for testing faults of a lamp.
It is a further object of the invention to avoid exposing the user to voltages of household power.
Still another object of the invention is to test lamps one by one.
An additional object of the invention is to provide both audible and visible annunciators.
Yet another object of the invention is to avoid problems which arise from inappropriate polarity in AC systems.
Still a further object of the invention is that the tester be applicable to all commonly utilized wiring schemes of light strings.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.